diff --git a/CHANGELOG.md b/CHANGELOG.md
index a314b10..8cb7e84 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## [Unreleased]
 
+### Changed
+- Bound the six previously unconstrained runtime dependencies in the gemspec: `ruby-openai ">= 7.1", "< 9"` (7.x and 8.x both verified against the suite), and `dry-schema ~> 1.13`, `zeitwerk ~> 2.6`, `ostruct ~> 0.6`, `logger ~> 1.6`, `cgi ~> 0.4` at their locked minors. Adding constraints where none existed is semver-visible: ship this as a minor bump. Closes #16.
+- Lockfile moved to ruby-openai 8.3.0 so CI tests what new consumers actually resolve.
+
 ### Fixed
 - Test suite loads on Ruby 4.0: `benchmark` is a bundled (not default) gem there, so it is now declared in the Gemfile
 - `EventDispatcher` slow-observer spec uses a monotonic clock and a looser bound so it no longer flakes on loaded hosts
diff --git a/Gemfile.lock b/Gemfile.lock
index a9dc9f1..5275371 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,12 +3,12 @@ PATH
   specs:
     agentic (0.2.0)
       async (~> 2.0)
-      cgi
-      dry-schema
-      logger
-      ostruct
+      cgi (~> 0.4)
+      dry-schema (~> 1.13)
+      logger (~> 1.6)
+      ostruct (~> 0.6)
       pastel (~> 0.8)
-      ruby-openai
+      ruby-openai (>= 7.1, < 9)
       thor (~> 1.2)
       tty-box (~> 0.7)
       tty-cursor (~> 0.7)
@@ -16,7 +16,7 @@ PATH
       tty-screen (~> 0.8)
       tty-spinner (~> 0.9)
       tty-table (~> 0.12)
-      zeitwerk
+      zeitwerk (~> 2.6)
 
 GEM
   remote: https://rubygems.org/
diff --git a/agentic.gemspec b/agentic.gemspec
index cbda719..e89a2ee 100644
--- a/agentic.gemspec
+++ b/agentic.gemspec
@@ -32,9 +32,9 @@ Gem::Specification.new do |spec|
   spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "dry-schema"
-  spec.add_dependency "ruby-openai"
-  spec.add_dependency "zeitwerk"
+  spec.add_dependency "dry-schema", "~> 1.13"
+  spec.add_dependency "ruby-openai", ">= 7.1", "< 9"
+  spec.add_dependency "zeitwerk", "~> 2.6"
   spec.add_dependency "async", "~> 2.0"
   spec.add_dependency "thor", "~> 1.2"
   spec.add_dependency "tty-spinner", "~> 0.9"
@@ -44,9 +44,9 @@ Gem::Specification.new do |spec|
   spec.add_dependency "tty-cursor", "~> 0.7"
   spec.add_dependency "tty-screen", "~> 0.8"
   spec.add_dependency "pastel", "~> 0.8"
-  spec.add_dependency "ostruct"
-  spec.add_dependency "logger" # bundled gem as of Ruby 3.5 - declare what you require
-  spec.add_dependency "cgi"    # trimmed to a bundled gem in Ruby 3.5; used for CGI.escape
+  spec.add_dependency "ostruct", "~> 0.6"
+  spec.add_dependency "logger", "~> 1.6" # bundled gem as of Ruby 3.5 - declare what you require
+  spec.add_dependency "cgi", "~> 0.4"    # trimmed to a bundled gem in Ruby 3.5; used for CGI.escape
 
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html